Natural and undisrupted liquid egg yolk contains microscopic sacs which contain protein, fat, water, and other components. When such natural and undisrupted liquid egg yolk is cooked (e.g., fried), a crumbly gel-like structure and texture is obtained. Once the microscopic sacs contained in the liquid egg yolk are disrupted, however, the egg yolk becomes rubbery and tough when cooked.
Numerous attempts have been made to prepare a simulated egg product having a distinct yolk portion and a distinct egg white portion (i.e., a simulated fried egg). None of these efforts of which are aware has been able to successfully compete with natural eggs in terms of consumer acceptance. Indeed, the most successful processed egg products on the market are the liquid or frozen egg substitutes such as, for example, EggBeaters.TM. and the like. These egg substitutes are suitable for scrambled eggs, omelettes, and recipes requiring whole eggs; such egg substitutes cannot, of course, simulate fried eggs or other egg products requiring separate yolk and egg white portions.
Shires, U.S. Pat. No. 3,863,018 (Jan. 28, 1975), provided a method to produced a simulated egg product using a solid, frozen core or stick of cooked egg yolk which was suspended in liquid egg whites in an elongated container. While maintaining the container in a vertical position and gently shaking the container to center the frozen yolk core, the egg whites were coagulated by either heating or freezing. The frozen yolk core was prepared by extruding cooked egg yolk in a stick-like form and then freezing until rigid. The egg product so produced could be cut into sections (i.e., patties) for use in sandwiches and the like.
Glasser et al., U.S. Pat. No. 3,941,892 (Mar. 2, 1976) provided a frozen egg product which simulated, at least in appearance, a sunnyside-up fried egg. A synthetic yolk material was used which contained dry egg white, oil, dry milk protein, gum, colors, flavoring, emulsifiers, and water. The yolk material along with the egg whites were frozen in an appropriate mold. The molded egg was then removed from the mold directly onto a cooking surface. As the yolk thawed during cooking, it tended to lose its shape "nearly to the point of running from its shape"; the shape was maintained only because the yolk coagulated before the shape was completely lost.
Forkner, U.S. Pat. No. 4,409,249 (Oct. 11, 1989), generally provided a process for preparing simulated eggs from homogeneous, aerated egg white dispersion and processed egg yolk. The assembled egg was frozen. In each case, the egg whites and yolk were treated separately and then combined; each could be separately pasteurized. A number of different processes, some of which involve frozen yolk bodies, were described. For all of these processes, the egg white was treated to effect a controlled degree of coagulation, after which the coagulated material (along with some uncoagulated material) was homogenized by high energy agitation with high shear forces. The homogenized egg white was then placed in an appropriate mold and topped with a predetermined weight of frozen yolk body. The assembled product could then be frozen and stored for extended periods. The egg yolk could be prepared from fresh eggs or from thawed commercial frozen egg yolk. The frozen egg yolk bodies could be used with or without an edible membrane formed by coating the frozen egg yolk body with a membrane-forming material (i.e., alginates, albumen, or waxes). The membrane was used to retain the yolk in the desired shape during subsequent thawing and cooking. Without this coating, the frozen yolk was subject to migration into, and mixing with, the egg white upon thawing and cooking; such uncoated egg yolk bodies were, therefore, more suited for preparing scrambled eggs and omelettes. In addition, Forkner acknowledged that the prior art provided for separating egg whites and egg yolk, depositing appropriate amounts of each into trays, and then freezing. But Forkner also reported that such a products, when thawed and cooked, tended to be "tough and lacking in palatability and flavor comparable to cooked fresh egg."
More recently, Vassiliou in U.S. Pat. No. 5,073,399 (Dec. 17, 1991) U.S. Pat. No. 5,149,561 (Sept. 22, 1992), U.S. Pat. No. 5,151,293 (Sep. 29, 1992), and U.S. Pat. No. 5,227,189 (Jul. 13, 1993) provided a simulated egg having separate yolk and egg white portions. The egg yolk was, however, a synthetic material containing an edible liquid, a colorant, and a negative thermoreversible gel former. The egg yolk and egg white portions were kept separate by a crust or shell which was formed around the yolk upon heating the yolk material containing the gel former.
None of the prior art relating to simulated egg patties or simulated egg products in general, of which are aware, provides suitable and acceptable egg patties from natural yolks and egg whites. It would be desirable, therefore, to provide a simulated egg patty made from natural egg yolk and egg whites having separate yolk and egg white portions. It would also be desirable to provide a simulated egg yolk and a simulated egg patty which have mouthfeel and texture similar to a fried egg prepared from a fresh egg. It would also be desirable to provide a simulated egg patty from pasteurized egg yolks and pasteurized egg whites. It would also be desirable to provide a relatively simple method by which such simulated egg yolks and simulated egg patties can be prepared. The present invention provides such simulated egg yolks and simulated egg patties as well as such a method.